Apparatus for binding book or sheets are generally well known; for example, see British Pat. Specification 1 446 115 and U.S. Pat. Nos. 3,920,501 and 3,902,646. In 3,902,646 an apparatus is disclosed in which a strip of binder material provided with a heat activated layer of glue is cut off to the size of the peripheral side of a stack of sheets to be bound. After the strip of binder material has been placed against the peripheral side of the stack of sheets to be bound, it is folded about the stack of sheets by heated folding plates. The layer of glue softens under these conditions, and the glue adheres to the individual sheets. After cooling, a set of sheets in book form is obtained, the set being covered by a binder strip at the spine.
The disadvantage of a binder apparatus of this kind is that some of the softened glue flows out at the ends of the strip of binder material due to the pressure exerted by the folding plates. This escaping glue soils both the folding plates and the bound stack of sheets. The soiling on the folding plates may contaminate not only the binder apparatus itself, but may also be deposited on the next stack of sheets that will be bond.
Accordingly it is an object of the invention to provide apparatus that overcomes the foregoing disadvantages.